Prime Minister Stephen Harper remained seated during in the House of Commons Tuesday and allowed his parliamentary secretary, sitting a few feet away, to answer a series of dissecting questions from NDP Leader Thomas Mulcair on the Senate scandal.

The real significance of the Mike Duffy saga is not the fate of one avaricious senator, or even whether his suspension by the Senate is “shameful, shocking and unconstitutional,” as his lawyer Donald Bayne charged in a remarkable press conference Monday.

Rather, it is whether the Prime Minister has been telling the truth, the whole truth and nothing but the truth to Parliament about the $90,000 cheque written by his former chief of staff, Nigel Wright, to cover the re-payment of Mr. Duffy’s housing expenses.

Statements in the House of Commons are not delivered under oath and the opposition parties have long expressed disbelief at Mr. Harper’s explanation that Mr. Wright was acting alone.

Tuesday’s question period was the first of the fall session in which the three main party leaders were all in attendance and it was marked by the direct, simple questions Mulcair asked the prime minister about Nigel Wright’s $90,000 cheque to Sen. Mike Duffy and other aspects of the growing scandal.

Before Harper allowed the parliamentary secretary to the prime minister, Ontario MP Paul Calandra, to take questions on the matter, the prime minister had a short exchange with the NDP leader.

“On June 5th, the prime minister said no one else in his office knew about Nigel Wright’s $90,000 payment to Mike Duffy. Was that true?” Mulcair asked Harper.

Harper responded: “Once again I’ve addressed that question some months ago in fact. The fact of the matter is this, as we all know Mr. Wright has said himself that this was a decision he made himself, that it was an error in judgment. He’s taken full responsibility and this government … will continue to take its responsibilities and those responsibilities are to focus on the real concerns of Canadians including jobs and the economy.”

Mulcair retorted: “As if whether or the not prime minister tells the truth to Canadians was not a matter of real concern to Canadians.”

After responding to Liberal Leader Justin Trudeau, who commended the government on the EU-Canada free trade deal, Harper sat down and let Calandra take questions for the prime minister from Mulcair.

“Nigel Wright said to Mike Duffy, and I quote ‘We have been working on lines and a scenario for you that would cover all of your concerns, including cash for repayment.’ Who’s we?” Mulcair asked.

The opposition roared and jeered when Calandra stood up instead of Harper.

“Wow, it’s certainly nice to be loved,” Calandra said.

“The prime minister has answered these questions very clearly on a number of occasions with all of the information he had available to him.”

Mulcair responded that Harper was the only one who could answer his question.

“Canadians will harshly judge the prime minister’s silence.”

Mulcair, who used truncated questions earlier this year in the House to great effect, continued with a number of very direct questions including:

“When the prime minister spoke to Mike Duffy in person on February 13th, was Nigel Wright there too?”

“On August 21st, long after he resigned, Nigel Wright gave the RCMP a binder full of documents related to the Mike Duffy affair. What’s in the binder?”

“Did the prime minister, or anyone else in his office, threaten Mike Duffy with expulsion from the Senate if he didn’t go along with the quote ‘cash for repayment’ scheme cooked up in his office.”

“December 2012, the prime minister’s chief of staff said that several senators had deals cooked up similar to that of Mike Duffy. Who were they?”

Calandra answered all the questions either by either saying the government had answered the question, Wright had taken full responsibility for the matter or they are continuing to work with the authorities.

Harper did stand up briefly to take one question on Wallin’s expenses during the exchange, but his answer was inaudible.

Earlier, in a rare instance for question period, Harper accepted a compliment from the opposition.

But Trudeau, who congratulated Harper and key members of hive government on the free trade deal, pivoted on his second question Tuesday saying: “Leaders take responsibility when things go well but also when thing go wrong. And clearly, when it comes to the scandal engulfing the PMO things have gone very wrong. Will the prime minister take any personal responsibility for this abuse of Canadians’ trust?”

Harper said those responsible for the issue have been dealt with but did not mention any names.

“As I’ve said, its unacceptable and those individuals in this affair have been dealt with and continue to be dealt with. We assure Canadians when things go wrong people will be held accountable.”

The exchange in question period occurred as Duffy and fellow former Tories, Sen. Pamela Wallin and Sen. Patrick Brazeau, made an appearance in the Senate to fight a motion to suspend them without pay.